1. Field of the Invention
The present invention relates to a green phosphor and a device using the same, more particularly to a green phosphor capable of converting a light applied into a light having a lower energy (a longer wavelength) and to a device using the green phosphor. The green phosphor of the present invention can be used suitably for gas discharge devices such as fluorescent lamps and display devices such as plasma display panels (PDPs).
2. Description of the Related Art
Phosphors are used widely in a variety of fields. For example, they are used for lighting devices such as fluorescent lamps, displays such as PDPs and X-ray camera tubes. For example in color display devices, three color phosphors, namely, a red, blue and green phosphors are used. By combining the fluorescences from the three color phosphors, a white color is produced. In particular, a green phosphor is an important one which determines the luminance of a white color. Therefore, the provision of a green phosphor which is capable of producing fluorescence of a high luminance and of a high color purity is awaited.
As conventional green phosphors, (Ba, Mn)Al12O19, (Y, Tb)BO3, and Zn2SiO4:Mn are well known. Moreover, though a blue phosphor, a phosphor represented by (BaMgAl10O17:Eu+2 in which part of Mg is replaced by Ca, Cu, Zn, Pb, Cd, Mg and Sn is also known (Japanese Unexamined Patent Publication No. 2002-173677).
Of the green phosphors mentioned above, (Ba, Mn)Al12O19 is high in color purity but low in luminance. On the other hand, (Y, Tb)BO3 is high in luminance but low in color purity.
Zn2SiO4:Mn is better balanced between color purity and luminance than the green phosphors mentioned above and therefore are widely used in display devices such as PDP.
However, even the color purity and luminance of Zn2SiO4:Mn are insufficient and further improvements in color purity and luminance are awaited.